n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 9 |
3 | 24 |
4 | 66 |
5 | 180 |
6 | 492 |
7 | 1344 |
8 | 3672 |
9 | 10032 |
10 | 27408 |
11 | 74880 |
12 | 204576 |
13 | 558912 |
14 | 1526976 |
15 | 4171776 |
16 | 11397504 |
17 | 31138560 |
18 | 85072128 |
19 | 232421376 |
20 | 634987008 |
21 | 1734816768 |
22 | 4739607552 |
23 | 12948848640 |
24 | 35376912384 |
25 | 96651522048 |
26 | 264056868864 |
27 | 721416781824 |
28 | 1970947301376 |
[1,3,9,24,66,180,492,1344,3672,10032,27408,74880, 204576,558912,1526976,4171776,11397504,31138560, 85072128,232421376,634987008,1734816768, 4739607552,12948848640,35376912384,96651522048, 264056868864,721416781824,1970947301376] |